JP6361149B2 - Lens barrel - Google Patents

Description

  The present invention relates to a lens barrel.

  In recent years, in particular, a lens barrel of a camera is required to have a small size and light weight, and to achieve high performance while achieving low cost.

  Since the lens barrel has a complicated structure, synthetic resin molded parts are often used in order to give priority to weight reduction and cost reduction, but the rigidity tends to be lower than that of metal molded parts. Therefore, in Patent Document 1, the rigidity of the manually operated ring that is a synthetic resin molded product is improved by using a reinforcing ring that is a metal molded part.

JP 2010-54600 A

  By the way, when using synthetic resin molded parts, downsizing is also required, so space-saving design has been carried out by reducing the thickness of the lens barrel, etc. The performance cannot be satisfied.

  Moreover, in addition to the lens group, the lens barrel may hold an optical component such as a diaphragm driving device or a flare cutter that regulates the light beam. If the opening is opened, the rigidity is further lowered.

  The present invention has been made to solve the above-described problems, and has an object to provide a lens barrel capable of satisfying high performance while achieving low cost with a small size and light weight by increasing rigidity. It is what.

  In order to solve the above problems, the lens barrel of the present invention is provided with a holding frame having two cylindrical portions that are arranged in parallel in the optical axis direction and can hold optical components. And between each said cylinder part, the inward protrusion part which protrudes inward rather than the inner surface of this each cylinder part is formed, It is characterized by the above-mentioned.

  According to the present invention, the connecting portions of the respective cylindrical portions are reinforced by the inward protruding portions formed between the two cylindrical portions that can respectively hold the optical components. Accordingly, even if the holding frame is made of synthetic resin and is reduced in size by reducing the thickness or the like, the rigidity is increased, so that optical components such as a lens group can be held with high accuracy.

  Also, since the connecting portion of the two cylindrical portions is adjacent to the inward protruding portion, the optical component held by the cylindrical portion is brought into contact with the inward protruding portion that can be formed with high strength and high accuracy. Therefore, the optical component can be held with higher accuracy.

  The inner surface of the inward projecting portion may have a substantially polygonal shape when viewed from the optical axis direction.

  According to this configuration, the rigidity is further increased by forming the inner surface of the inward protruding portion in a substantially polygonal shape.

  A concave portion is formed on the outer surface of the inward projecting portion, and the bottom surface of the concave portion can be configured to have a substantially polygonal shape when viewed from the optical axis direction.

  According to this configuration, the rigidity is further increased by forming the bottom surface of the concave portion on the outer surface of the inward protruding portion in a substantially polygonal shape.

  The holding frame may be made of a synthetic resin, and the concave portion of the inward protruding portion may be formed to have a substantially constant thickness.

  According to this configuration, the holding frame is made of synthetic resin, thereby reducing weight and cost. In addition, by forming the concave portion so that the thickness is substantially constant, deformation at the time of molding such as sink marks is difficult to occur while securing rigidity, and the molding accuracy is stabilized.

  The substantially polygonal shape may be configured to be a substantially trigonal to octagonal shape.

  According to this configuration, the holding frame can be formed with a reduced size.

  The substantially polygonal shape of the inner surface of the inward protruding portion or the bottom surface of the concave portion can be configured such that adjacent flat portions are connected by an arc portion.

  According to this configuration, the molding process becomes easier and the shape is effective for securing the rigidity than when the corner portions between the adjacent flat portions remain.

  The recess may have a structure in which a rib connected to the outer surface of each cylindrical portion is formed.

  According to this configuration, since the concave portion is reinforced by the rib, the rigidity is further increased.

  The optical component can be held on the inner surface of the inward protruding portion.

  According to this configuration, since the inner diameter protrusion has high rigidity, the optical component can be held with high accuracy on the inner surface of the inner protrusion.

  It is possible to adopt a configuration in which a diaphragm driving device is held adjacent to the inward projecting portion in one of the tube portions.

  According to this configuration, the aperture driving device requires a large space in the radial direction, and it is necessary to open an interlocking opening in the cylindrical portion for mechanical or electrical interlocking with the camera body. Therefore, it is possible to secure the rigidity of the cylindrical portion by holding the aperture driving device and making the large-diameter cylindrical portion formed with the interlocking opening adjacent to the inward protruding portion.

  A fixed cylinder and a cam cylinder are provided on the outer surface of the holding frame, and the holding frame is configured to be held movably in the optical axis direction by either the fixed cylinder or the cam cylinder. Moreover, it can be set as the structure by which the biasing member contact | abutted to the said fixed cylinder or the said cam cylinder is provided in the recessed part of the said inward protrusion part.

  According to this configuration, when the holding frame is configured to reciprocate in the optical axis direction to perform focusing or the like, the holding frame is urged against the fixed component (plate spring) in order to suppress performance degradation due to rattling. Etc.). In this case, since the urging member can be provided using the concave portion of the inward protruding portion, it is not necessary to increase the diameter of each cylindrical portion in order to provide the urging member. Can be planned.

  A fixed cylinder, a cam cylinder, and an exterior member are provided on the outer surface of the holding frame, and a rear bottom portion of the front cylinder portion of the holding frame is coupled to a rear end portion of the cam cylinder and the fixed cylinder and the exterior member. It can be set as the structure which is located ahead rather than a part and has overlapped with the said connection part in radial direction.

  According to this configuration, it is possible to further reduce the size by overlapping the rear bottom portion with the coupling portion in the radial direction.

  According to the present invention, by increasing the rigidity of the holding frame, it is possible to satisfy high performance while achieving low cost with a small size and light weight.

It is sectional drawing of the optical axis direction of the lens barrel which concerns on this invention. It is a disassembled perspective view of a holding frame part. (A) is a perspective view of a holding frame, (b) (c) is a front view of a modification of a polygonal shape. (A) and (b) are operation | movement explanatory drawings of the metal mold | die which shape | molds the inner surface of the inward protrusion part of a holding frame, and the inner surface of a cylindrical part. (A)-(d) is operation | movement explanatory drawing of the metal mold | die which shape | molds the whole holding frame.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of the lens barrel in the optical axis OA direction. FIG. 2 is an exploded perspective view of the holding frame portion.

  The lens barrel includes a cylindrical fixed cylinder 1 extending in the direction of the optical axis OA, and an exterior member 2 that surrounds the outer periphery of substantially the latter half of the fixed cylinder 1 at the rear end of the fixed cylinder 1, and a camera body A mounting member 3 for attachment to (not shown) is fixed with screws or the like.

  A cam cylinder 4 is rotatably fitted to the outer surface of the fixed cylinder 1 located inside the exterior member 2, and a gear portion (not shown) of the cam cylinder 4 is fixed to the outer peripheral portion of the fixed cylinder 1. The gear is coupled to a focus switching gear unit (not shown). An AF (autofocus) motor and a manual operation ring 5 are gear-coupled to the focus switching gear unit so that AF and MF (manual focus) can be selected.

  The operation ring 5 is disposed so as to surround the outer periphery of the substantially front half of the fixed cylinder 1, and includes a convex portion 1 a of the fixed cylinder 1 and an operation ring pressing member 6 fixed to the front end of the fixed cylinder 1 with a screw or the like. Thus, the rotation in the direction of the optical axis OA is regulated and supported manually so as to be freely rotatable.

  The first lens group unit 8 is fitted to the operation ring pressing member 6 and fixed by a front stop ring 9.

  An AF motor, an electric board (not shown), and a focus encoder flexible board 10 are respectively fixed to the outer surface of the fixed cylinder 1 and are electrically connected to each other. The electric board is electrically connected to an electric contact provided on the mount member 3 via a flexible connecting board (not shown).

  A brush contact piece 4 a is attached to the cam cylinder 4, and the rotational position of the cam cylinder 4 can be detected by contacting the brush contact piece 4 a with the focus encoder flexible substrate 10.

  The fixed cylinder 1 is provided with a rectilinear groove, and the cam cylinder 4 is provided with three sets of cam grooves at substantially equal angular intervals on the circumference, and three followers 11c integrally formed with the holding frame 11 pass through the rectilinear groove and are cam grooves. Will come into engagement. As a result, the holding frame 11 can reciprocate (focus) in the direction of the optical axis OA by the rotation of the cam cylinder 4.

  The holding frame 11 is made of a synthetic resin (for example, PC... Polycarbonate) to which a light shielding material such as carbon black is added. The holding frame 11 is arranged in parallel in the direction of the optical axis OA and can hold optical components. It has two cylindrical portions 11a and 11b.

  The cylindrical portion 11a on the front side (subject side) of the holding frame 11 in the optical axis OA direction has a large diameter, and the cylindrical portion 11b on the rear side (focal plane side) has a small diameter.

  The second lens group unit 12 is fitted and held in the front cylindrical portion 11a, and the third lens group unit 13 is fitted and held in the rear cylindrical portion 11b.

  A diaphragm driving device (holding member, diaphragm blade, driving plate, etc.) 14 is incorporated in the front cylindrical portion 11a between the rear bottom portion 11d and the second lens group unit 12. The driving plate of the diaphragm driving device 14 has an arm portion extending rearward through an interlocking opening 11e (see FIG. 3A) formed in the rear bottom portion 11d. The aperture lever 15 provided on the mount member 3 is linked to the rotation direction so as to be freely movable in the direction of the optical axis OA. Thereby, even if the holding frame 11 including the aperture driving device 14 moves back and forth in the direction of the optical axis OA by the focus drive, the interlocking state can be maintained, and the aperture diameter can be adjusted by operating the aperture lever 15 from the camera body side. can do. There is a type in which only the aperture driving device 14 is incorporated in the front cylindrical portion 11a, or a type in which only the second lens group unit 12 is incorporated.

  As shown in FIG. 1, the rear bottom portion 11 d is positioned in front of the rear end portion of the cam cylinder 4 and the coupling portion where the fixed cylinder 1 and the exterior member 2 are coupled, and overlaps the coupling portion in the radial direction. Yes. Thereby, size reduction can be achieved by overlapping the rear bottom portion 11d with the coupling portion in the radial direction.

  Between the front cylindrical portion 11a and the rear cylindrical portion 11b of the holding frame 11, an annular inward projection that protrudes inward from the inner surfaces of the cylindrical portions 11a and 11b, that is, in the center direction of the optical axis OA. The part 11f is integrally formed.

  The inner surface of the inward protruding portion 11f may be substantially circular as viewed from the direction of the optical axis OA, but is preferably substantially regular polygonal as shown in FIG.

  An annular recess 11g is integrally formed on the outer surface of the inward projecting portion 11f. When the holding frame 11 is made of a synthetic resin, it is preferable to form the concave portion 11g of the inward projecting portion 11f so that the thickness is substantially constant.

  The bottom surface of the recess 11g may be substantially circular as viewed from the direction of the optical axis OA, but preferably has the same regular polygonal shape as the inner surface of the inward projecting portion 11f as shown in FIG.

  The substantially regular polygonal shape in FIG. 4 is a substantially hexagonal shape, but it may be a triangle as shown in FIG. 3B or a quadrangle as shown in FIG. 3C, and although not particularly shown, a pentagon, heptagon, octagon, More squares may be used.

  When the substantially polygonal shape of the inner surface of the inward projecting portion 11f (hereinafter, including the bottom surface of the recess 11g unless otherwise specified) is a substantially hexagonal shape as shown in FIG. It is preferable to set in an angle range θ of 40 to 55 degrees. Moreover, it is preferable to connect between the adjacent flat parts 11h by the circular arc part 11i.

  When the angle range θ of the flat part 11h is narrow, the improvement in rigidity of the holding frame 11 is small, and when the flat part 11h is used as a contact surface of a component, the contact area becomes narrow. On the other hand, if the angle range of the flat portion 11h is too wide, the corner portion extends outward, so the difference between the inner and outer diameters increases, the required space in the radial direction increases, and the mold is held due to restrictions on the mold. It may be difficult to form the frame 11.

  It is preferable that a plurality of ribs 11j in the direction of the optical axis OA connected to the outer surfaces of the adjacent cylindrical portions 11a and 11b are formed on the flat portion 11h of the recess 11g.

  The end surface of the third lens group unit 13 fitted to the rear cylindrical portion 11b is in direct contact with the inner end surface of the inward projecting portion 11f, and is fixed to the holding frame 11 by screw connection or by screws. ing.

  The third lens group unit 13 is fitted to an inscribed circle of a substantially hexagonal flat portion 11h, which is the inner surface of the inward protruding portion 11f, instead of the rear cylindrical portion 11b, and is in a six-point contact. It can also be held. In this case, the inward projecting portion 11f has higher rigidity than the rear cylindrical portion 11b and can be held with high accuracy. In addition, a flare cutter or the like that regulates the light beam can be fitted to the inscribed circle of the flat portion 11h of the inward projecting portion 11f and held by 6-point contact.

  The second lens group unit 12 fitted to the front cylindrical portion 11a is fixed by a pressing washer 17 in contact with the convex portion 11d at the bottom of the cylindrical portion 11a. Similarly, the holding frame 11 can be fixed with screws.

  A base portion of a bifurcated leaf spring (biasing member) 18 that enters the hollow portion 11m of the front cylindrical portion 11a from both sides of the follower 11c and contacts the inner surface of the fixed cylinder 1 in the flat portion 11h on the bottom surface of the concave portion 11g. 18a is fixed. A projection 11k is formed on the flat portion 11h on the bottom surface of the recess 11g, and the plate spring 18 is positioned on the flat portion 11h on the bottom surface of the recess 11g by fitting the hole 18b of the base portion 18a into the projection 11k. . In the type in which the cam cylinder 4 is disposed on the inner surface side of the fixed cylinder 1, the leaf spring 18 is brought into contact with the inner surface of the cam cylinder 4.

  Next, a mold for molding the holding frame 11 made of synthetic resin will be described. FIGS. 4A and 4B are operation explanatory views of the first mold 21 for molding the inner surface of the inward projecting portion 11f and the inner surfaces of the cylindrical portions 11a and 11b. FIGS. 5A to 5D are operation explanatory views of the first mold 21 to the fifth mold 25 for molding the entire holding frame 11.

  4A shows the mold position during molding, and FIG. 4B shows the mold position when the holding frame 11 is taken out.

  When the inner surface of the inward projecting portion 11f is substantially hexagonal, the first mold 21 is divided into six equal parts at substantially equal angular intervals on the circumference, and three positions of 0 degrees, 120 degrees, and 240 degrees are provided. The split mold 21A and the split mold 21B at three positions of 60 degrees, 180 degrees, and 300 degrees.

  The split mold 21A has an arcuate shape that molds approximately one-sixth of the inner surface of the rear cylindrical portion 11b and the flat surface 11h that forms the left and right arc portions 11i connected to the flat portion 11h. And a molding surface 21b.

  The split mold 21B has a flat molding surface 21c that molds the flat portion 11h and an arc-shaped molding surface 21d that molds approximately one sixth of the inner surface of the rear cylindrical portion 11b.

  Although not specifically shown in FIG. 4, the split molds 21A and 21B have arc-shaped molding surfaces 21e and 21f for molding approximately one sixth of the inner surface of the front cylindrical portion 11a (see FIG. 5). Also have each.

  When moving from the molding of FIG. 4A to the removal of the holding frame 11 of FIG. 4B, first, the split mold 21B at the three positions is moved inward, that is, toward the center of the optical axis OA. Then, the split mold 21A at the three positions is simultaneously moved inward, that is, toward the center of the optical axis OA. At this time, the arc-shaped molding surface 21d of the split mold 21B moves greatly inward of the flat portion 11h, and the arc-shaped molding surface 21b of the split mold 21A also has a slight gap inward of the flat portion 11h. To move.

  Thereby, as will be described later, the molded holding frame 11 can be taken out from the first mold 21 in the direction of the rear cylindrical portion 11b.

  FIG. 5A shows a mold position when the entire holding frame 11 is molded. The 2nd metal mold | die 22 shape | molds the outer surface of the inward protrusion part 11f, and the outer surface of cylindrical part 11a, 11b. The third mold 23 is for molding the rear end of the cylindrical portion 11 b on the rear side of the holding frame 11. The fourth mold 24 is for molding the front end of the cylindrical portion 11 a on the front side of the holding frame 11. The fifth mold 25 holds the first mold 21 in the molding position. Each of the molds 21 to 25 is a split mold for convenience of molding.

  When moving from the molding shown in FIG. 5A to the holding frame 11 shown in FIG. 5D, the third mold 23 and the fifth mold 25 are first moved in the direction of the arrow. Then, as shown in FIG. 5B, the second mold 22 and the first mold 21 are moved in the direction of the arrow. In addition, the movement of the 1st metal mold | die 21 is as having demonstrated in FIG.

  In the state of FIG. 5C, the molded holding frame 11 is held by the fourth mold 24. Even in this state, the inner surface of the inward projecting portion 11f and the first mold 21 Since there is a gap S between them, the first mold 21 can be taken out in the direction of the rear cylindrical portion 11b.

  In the case of the lens barrel configured as described above, the holding frame 11 has two cylindrical portions 11a and 11b capable of holding optical components such as the lens group units 12 and 13, the aperture driving device 14, and the flare cutter, respectively. An inward protruding portion 11f is formed between the two. The inwardly protruding portion 11f reinforces the connecting portion of the cylindrical portions 11a and 11b. Therefore, even if the holding frame 11 is made of a synthetic resin and is reduced in size by reducing the thickness or the like, the rigidity is increased, so that the optical parts such as the lens group units 12 and 13 can be held with high accuracy. Become.

  Further, since the connecting portion of the two cylindrical portions 11a and 11b is adjacent to the inward projecting portion 11f, the inner part that can form the optical component held by the cylindrical portions 11a and 11b with high strength and high accuracy. It can be brought into contact with the protruding portion 11f. As a result, the optical component can be held with higher accuracy.

  Furthermore, the rigidity is further increased by forming the inner surface of the inwardly projecting portion 11f in a substantially polygonal shape.

  Further, the rigidity is further increased by forming the bottom surface of the concave portion 11g on the outer surface of the inward protruding portion 11f in a substantially polygonal shape.

  Furthermore, when the holding frame 11 is made of synthetic resin, the weight is reduced and the cost is reduced. In addition, by forming the concave portion 11g so that the thickness is substantially constant, deformation during molding such as sink marks is difficult to occur while securing rigidity, and molding accuracy is stabilized.

  Further, if the substantially polygonal shape is substantially a trigonal to octagonal shape, the holding frame can be formed with a reduced size.

  Furthermore, the substantially polygonal shape of the inner surface of the inward projecting portion 11f or the bottom surface of the concave portion 11g connects the adjacent flat portions 11h with an arc portion 11i. Therefore, it is easier to form and effective in securing rigidity than when the corners between the adjacent flat portions 11h remain.

  Further, if the rib 11j is formed in the recess 11g, the recess 11g is reinforced by the rib 11j, so that the rigidity is further increased.

  Furthermore, if optical components such as the third lens group unit 13 and the flare cutter are held on the inner surface of the inward projecting portion 11f, the inward projecting portion 11f has high rigidity. Parts can be held with high accuracy.

  Further, if the aperture driving device 14 is held in the large diameter cylindrical portion 11a adjacent to the inward projecting portion 11f, the aperture driving device 14 needs a large space in the radial direction. In addition, it is necessary to open the interlocking opening 11e in the cylindrical portion 11a for mechanical or electrical interlocking with the camera body. Therefore, it is possible to secure the rigidity of the cylindrical portion 11a by holding the aperture driving device 14 and making the large-diameter cylindrical portion 11a formed with the interlocking opening 11e adjacent to the inward protruding portion 11f.

  Further, when the holding frame 11 is reciprocally moved in the direction of the optical axis OA to perform focusing or the like, the holding frame 11 is urged against a fixed component (such as a leaf spring) in order to suppress performance degradation due to rattling. ) Need to be energized. In this case, since the leaf spring 18 can be provided by using the recess 11g of the inward projecting portion 11f, the cylindrical portions 11a and 11b do not have to have a large diameter in order to provide the leaf spring 18. Further downsizing can be achieved.

DESCRIPTION OF SYMBOLS 1 Fixed cylinder 2 Exterior member 4 Cam cylinder 11 Holding frame 11a Front cylindrical part (cylinder part)
11b Cylindrical part (cylinder part) on the rear side
11d Rear bottom part 11e Interlocking opening 11f Inward projecting part 11g Concave part 11h Flat part 11i Arc part 11j Rib 12, 13 Lens group unit (optical component)
14 Aperture drive (optical components)
15 Diaphragm lever 18 Leaf spring (biasing member)
OA optical axis

Claims (9)

A holding frame that is arranged in parallel in the optical axis direction and has two cylindrical portions each capable of holding optical components is provided, and protrudes inward from the inner surface of each cylindrical portion between the cylindrical portions. An inward protrusion is formed,
A concave portion is formed on the outer surface of the inward protruding portion, and the bottom surface of the concave portion is substantially polygonal when viewed from the optical axis direction,
The recess is formed on the outer surface immediately of the inward protrusion,
The cross section of the inward projecting portion when cut by a plane including the optical axis is formed in a U-shape having a substantially constant thickness by the concave portion ,
The lens barrel characterized in that the inner surface of the inward projecting portion has a substantially polygonal shape when viewed from the optical axis direction . The lens barrel according to claim 1, wherein the holding frame is made of a synthetic resin. The substantially polygonal shape, a lens barrel according to claim 1 or 2, characterized in that a substantially three to eight square. Substantially polygonal shape of the bottom surface of the inner surface or the recess of the inner protrusion, the lens according to any one of claims 1 to 3, characterized in that between the flat portions adjacent are connected by an arc section The lens barrel. Wherein the concave lens barrel according to any one of claims 1 to 4, characterized in that the ribs connected to the outer surface of the respective cylindrical portion. Wherein the inner surface of the inwardly projecting portion, the lens barrel according to any one of claims 1 to 5, wherein the component optical is characterized in that it is holding. The lens barrel according to any one of claims 1 to 6 , wherein a diaphragm driving device is held adjacent to the inward projecting portion in any one of the tube portions. A fixed cylinder and a cam cylinder are provided on an outer surface of the holding frame, and the holding frame is configured to be held movably in the optical axis direction by either the fixed cylinder or the cam cylinder, and the inward projecting portion concave lens barrel according to any one of claims 1 to 7, characterized in that said fixed cylinder or the cam barrel to abut the biasing member is provided for. A fixed cylinder, a cam cylinder, and an exterior member are provided on the outer surface of the holding frame, and a rear bottom portion of the front cylinder portion of the holding frame is coupled to a rear end portion of the cam cylinder and the fixed cylinder and the exterior member. positioned in front of the parts, the lens barrel according to any one of claims 1 to 7, characterized in that by overlapping the coupling portion and radially.

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